The invention relates to regulating arrangements. More particularly, the invention relates to regulating arrangements including a movable component whose motion is to be controlled and an electrical mover which moves the movable component in accordance with command signals applied to the mover. The electrical mover can be a conventional D.C. motor, a galvanometer-type mover, an electromechanical transducer of the sliding-core type, or any of a host of other well known electrical movers and transducers used in servomechanisms and other types of control systems.
The invention relates, inter alia, to extremely well known problems arising from the control of a movable component indirectly through an intermediate electrical mover. In many control systems the system response is far from the theoretical ideal, and the commanded performance is actually achieved only after an undesirable delay, or not at all, or only with undesired overshoots and oscillation, etc. It is known in the art to improve various aspects of system response by the use of such expedients as error-rate damping, integral error compensation, output-derivative feedback damping, and other expedients.
Tachometric feedback damping, for example, involves subtracting from the activating signal for the electrical motor a signal proportional to the speed of the electrical motor. The activating signal is proportional to the difference between the actual and desired values of a controlled variable, such as for instance the angular orientation of the rotor of the motor. The subtration from the activating signal of the speed-proportional tachometer voltage results in damping of the system response, and in a decreased tendency to overshoot the desired final position. Details of tachometric feedback damping are well known, and reference is made for example to "Control Systems Engineering," by Del Toro and Parker, McGraw Hill, New York, 1960, pp. 132 ff.
An important practical disadvantage of tachometric feedback damping is the use of a tachometer generator for producing the feedback signal proportional to motor speed. Clearly, the tachometer generator adds to the cost of the system, may in some circumstances be bulky, and may be difficult to fit into a system already built and not having tachometric feedback damping.